Apparatus and method for providing uninterrupted continuous play during a change of sides of a dual-sided optical disk

ABSTRACT

An apparatus and method for providing continuous uninterrupted playback of a dual sided optical disk during side-to-side changing of the optical disk. The point at which a dual-sided optical disk will be switched between sides is determined. At some point prior to the switching of sides of the disk, a portion of the data at the end of the first side of the disk is transferred to a memory. During the switching of the disk to the second side, the stored data is read out from the memory to provide uninterrupted continuous playback of the optical disk.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an optical disk system forplaying back signals from a recorded media, and more particularly to avideo disk apparatus which provides uninterrupted continuous playback ofa dual-sided optical disk during the period of switching from one sideof the disk to the other side of the disk.

2. Description of the Related Art

Generally, optical disks have tracks that can record and play backvarious types of data. Common optical disks include compact disks (CDs),CD-ROMs, digital video disks or digital versatile disks (DVDs), or othersimilar disks. Some optical disks, such as DVDs, may be eithersingle-sided or dual sided, i.e., data may be stored on only one or bothsides of the disk.

In the situation where data is stored on both sides of the optical disk,the optical disk must be “flipped” from one side to the other in orderto read data from both sides of the disk, or the playback apparatus mustbe capable of reading both sides of the disk without the disk being“flipped” over. Generally, a conventional optical disk recording andplayback device uses one optical pickup to record or playback data onthe tracks of a side of the disk adjacent to the optical pickup. Uponcompletion of the recording and playback of data on the side of tie diskadjacent to the optical pickup, the disk is flipped, either by humanmanual intervention or an automatic changing device, to access the datafrom the other side of the disk. The manual flipping of the disk mayrequire that the disk be taken out of the optical disk recording andplayback device and then reinserted back into the optical disk recordingand playback device.

In the case of an optical disk recording and playback device which hasan automatic changing device, a rotatable transfer mechanism may be usedto load a disk to an optical reader. The optical pickup is locatedwithin the optical reader to access the data on the side of the diskfacing the optical pickup. When the first side of the disk has been readby the optical pickup, the disk will be transferred from the opticalreader back into the transfer mechanism, the transfer mechanism rotatedabout its axis, and the disk reinserted back into the optical readerwith the second side facing the optical pickup.

However, there are limitations with respect to the operation of devicesin which the disk is flipped, either manually or automatically. Thereproduction of the video signals must be stopped while the disk isbeing flipped until the data on the second side of the disk can beaccessed. As a result, a video picture is stopped on a screen for theperiod of time required for the disk to be flipped, thus interrupting amovie or game program stored on the disk.

Alternatively, devices have been developed in which the data on bothsides of an optical disk can be continuously accessed without the needfor manually or automatically flipping the disk. Such devices may employeither one or two optical pickups.

An example of a continuous both-side playback device utilizing a singlepickup is illustrated in U.S. Pat. No. 5,257,111. The single pickup isadapted to read the video signals recorded on both sides of the videodisk by moving along a U-shaped track from the center of the top side ofthe disk to the center of the bottom side of the disk around the edge ofthe disk. However, there are limitations associated with this type ofdevice similar to those in which the disk is flipped. Namely, thereproduction of the of the video signals must be stopped during the timethe second side of the disk is being accessed, i.e., while the pickupmoves from the outer circumference of the lower side of the video diskto the inner circumference of the upper side of the video disk to readthe video signals recorded on the upper side of the video disk afterreading all the video signals recorded on the lower side of the videodisk. As a result, a video picture is stopped on a screen for about10-15 seconds, thus interrupting the movie or game program stored on thedisk.

An example of a continuous both-side playback device utilizing twopickups is illustrated in U.S. Pat. No. 5,448,373. A first pickup isprovided to read data from the top side of the disk, and a second pickupis provided to read the data from the lower side of the disk, thusremoving the necessity for flipping the disk. During operation, thevideo disk is rotated in a counter-clockwise direction to read the videosignals recorded on the lower side of the video disk. The rotation isthen halted and reversed to a clockwise direction to read the videosignals recorded on the upper side of the video disk. To overcome theproblem of the time required to reverse the rotation of the video diskfrom the counter-clockwise direction to the clockwise direction(approximately 4-6 seconds) and the resulting stoppage of the videopicture on the screen, both sides of the video disk are read and storedin a memory. The contents of the memory are then output so that thevideo signals from both sides of the disk can be successively reproducedwith no discontinuity. However, this type of device requires anextensive amount of memory space to store the entire contents of bothsides of the disk. The extensive amount of memory required results inboth increased costs for the device and an increase in physical size ofthe device.

Therefore, although the conventional optical disk systems are capable ofcontinuous playback of dual-sided optical disks, they do not provide anapparatus or method for uninterrupted continuous playback withoututilizing an extensive amount of memory to store the entire datacontents of both sides of the disk before playback. Thus, there exists aneed for an optical disk system that is capable of continuously playingback signals from a double-sided recorded media without interruptionwhen the side being read is switched, without requiring an extensiveamount of memory space.

SUMMARY OF THE INVENTION

The present invention overcomes the problems associated with the priorart and provides a unique method and apparatus for providinguninterrupted continuous play of a dual sided optical disk duringside-to-side changing of the disk.

In accordance with the present invention a portion of the data from theend of the first side of an optical disk is read and stored in a memory.During playback of the disk by the system, the data on the first side ofthe disk is read up to the point where the data has been stored in thememory. When this point has been reached, the data previously stored inthe memory is read out to the system, and the disk or reading mechanismis simultaneously switched from the first side to the second side toallow access to data on the second side of the disk. When the datastored in the memory has completed being read out to the system, thedisk or reading mechanism has already completed tie switch from thefirst side to the second side. The data on the second side of the diskis then read in succession with the data stored in the memory. Since thedata being read by the system does not have to stop during the switchingof sides of the disk, the system provides uninterrupted continuousplayback of the disk. Additionally, since only a small portion of thedata needs to be stored in a memory, the size of the required memorylocation is minimized, thus reducing the hardware requirements of thesystem.

These and other advantages and features of the invention will becomeapparent from the following detailed description of the invention whichis provided in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates in block diagram form an optical disk device capableof providing continuous uninterrupted playback of an optical disk duringside-to-side changing of the disk in accordance with the presentinvention;

FIG. 2 illustrates in flow chart form a method of providing continuousuninterrupted playback of an optical disk during side-to-side changingof the disk in accordance with the present invention; and

FIG. 3 illustrates in block diagram form a system in which the opticaldisk device in accordance with the present invention may be utilized.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described as set forth in the preferredembodiment illustrated in FIGS. 1-3. Other embodiments may be utilizedand structural, logical or programming changes may be made withoutdeparting from the spirit or scope of the present invention.

FIG. 1 illustrates generally in block diagram form an optical diskdevice 100 capable of providing continuous uninterrupted playback of anoptical disk during side to side switching of the disk in accordancewith the present invention. Optical disk device 100 generally includes adisk drive controller 108, a memory device 110, and an optical reader104 for reading an optical disk 102. Optical disk 102 may be a compactdisk (CD), CD-ROM, digital video disk or digital versatile disk (DVD),or the like. A transfer mechanism 106 may be provided for flipping thedisk 102 to access both sides of the disk 102 in the case where it isdual-sided. Alternatively, the optical reader 104 may be able to rotateor may include means for accessing both sides of disk 102 without havingto flip the disk by a transfer mechanism 106, or the device 100 mayinclude any other method of accessing the second side of the disk 102.The data from the disk 102 is processed and output on output line 112,which may connect to an output device 114, such as a video monitor,computer, game device or other device or system which requires the datacontained on optical disk 102.

Optical disk device 100 operates as follows. Optical disk 102 isinserted into optical reader 104. Optical reader 104 includesconventional sensors and electronics for reading optical disk 102.Controller 108 determines the point at which the reading of disk 102will be switched between sides. Controller 108 may include amicroprocessor. The microprocessor may be any conventional generalpurpose single- or multi-chip microprocessor. In addition, themicroprocessor may be any conventional special purpose microprocessorsuch as a digital signal processor or a graphics processor.

The time required for the system to switch sides of the disk 102 toaccess the second side of the disk 102, whether it be by transfermechanism 106 or some other means within optical reader 104 or withinthe device 100, is known based on the time required for operation of thetransfer mechanism 106 and may be stored in a ROM within controller 108or programmed directly into controller 108. Controller 108 will cause atransfer of a portion of data from the first side of the disk 102 tomemory device 110. The portion of data transferred may be equivalent toan amount of data that, when read by the system, corresponds to theamount of time required for the optical disk device 100 to access thesecond side of the disk 102. Memory device 110 may be a dedicated memorydevice that is capable of storing the data read from disk 102, or may bepart of a standard computer system allocated to store the data from disk102.

When the device 100 is activated to playback the disk 102, the opticalreader 104 starts to read data stored on the first side of the disk 102.When the beginning address of the data that has been transferred tomemory 110 has been reached, the data previously transferred from disk102 to memory 110 will be output by controller 108. While the datapreviously transferred to and stored in memory device 110 is being read,optical disk 102 is switched between the first side and the second sideby transfer mechanism 106. Alternatively, if transfer mechanism 106 isnot provided, the second side of disk 102 may be accessed by any methodas known in the art.

The switching of sides of disk 102 will be completed at approximatelythe same time as or before the data stored in memory 110 has finishedbeing read, since the amount of data transferred to memory 110 willrequire at least the same amount of time to be read out as it takes forthe device 100 to switch reading between sides of disk 102. Thisprovides for access to the data stored on the second side of disk 102 assoon as the data stored in memory 110 has been read out from device 100.For example, controller 108 may be used to monitor the address of thedata as it leaves memory 110. When the last address of the data from thefirst side of disk 102 stored in memory 110 has been read out,controller 108 will cause optical reader 104 to commence reading data onthe second side of disk 102 with the next sequential address. Thus, inaccordance with the present invention, a seamless transition from afirst side to a second side of an optical disk 102 is provided withouthaving a video picture stopped on a screen for the period of time ittakes for the system to switch between sides of the disk 102.Additionally, since only a small portion of the data stored on the firstside of the disk 102 is transferred to memory 110, the size of thememory 110 can be minimized to reduce the physical size and cost of thedevice 100.

The method for providing uninterrupted continuous playback of a dualsided optical disk in accordance with the present invention isillustrated generally at 200 in FIG. 2. In step 210, a dual sidedoptical disk is loaded into an optical reader in any manner as is knownin the art. The optical disk may be a compact disk (CD), CD-ROM, digitalvideo disk or digital versatile disk (DVD), or any other such opticaldisk. The optical reader may be any type of optical reader as is knownin the art, including readers with one or two optical pickups, andincludes conventional electronics and sensors for reading an opticaldisk. Additionally, the optical reader may be used in any type ofapparatus that utilizes any method for accessing both sides of a diskknown in the art, including automatically flipping the disk or providingmeans for reading both sides of the disk without flipping the disk, toname a few.

When a dual sided optical disk is loaded into the optical reader, thedata will typically be read from a first side and then a second side ofthe disk consecutively. In step 212, an address representing the pointat which the reading of data from the optical disk will be switched fromthe first side to the second side is determined. The determination ofthis address point, as further described below, may typically beperformed by a control circuit.

Once the determination of the point at which the reading of the diskwill be switched between sides has been made in step 212, a portion ofthe data stored on the first side of the disk is read and transferred toa memory in step 214. The portion of the data transferred includes thedata from the address point determined in step 212 on the first side ofthe disk up to and including the point at which the data ends on thefirst side of the disk. The determination of the point at which thereading of the disk will be switched between sides and resulting size ofthe portion of data stored in the memory is typically based on thefunctional capabilities of the optical disk system in which the opticalreader is employed. The amount of data stored in the memory will requirea certain amount of time to be read out from the memory. The amount oftime required to read the data from the memory corresponds to the amountof time required for the optical disk system to switch the reading ofthe sides of the disk to allow access to the data stored on the secondside of the disk. Thus, by varying the amount of data transferred to thememory, the amount of time required for the data to be read out of thememory can also be varied to coincide with the time required to switchsides of the disk.

For example, the optical disk system may incorporate a transfermechanism that receives the disk after the first side has been played,flips the disk from the first side to the second side, and reinserts thedisk back into the optical reader. Alternatively, the disk may beremoved from the optical reader, the optical reader rotated about anaxis, and the disk reinserted so the optical pickup faces the secondside of the disk. This process may take a number of seconds, such as forexample, 10 seconds. The determined address point on the disk at whichpoint the reading of the optical disk will be switched between sides andthe resulting portion of data to be stored in memory will be someaddress point prior to or equivalent to the address point at which thereis 10 seconds of data left on the first side of the disk, such as forexample 12 seconds. Thus, the size of the portion of data from the firstside of the disk that is transferred to the memory may correspond to theamount of time required for the optical disk system to access the secondside of the disk. Since the amount of time required to switch thereading of the data from the first side of the disk to the second sideof the disk is known, the address point at which to start the datatransfer can be easily determined by a controller in the system.

In step 216, the system starts to read the data from the first side ofthe disk. The data is read by conventional sensors and electronics forreading an optical disk included in the optical reader. In step 218, thesystem determines whether the address of the determined point from whichthe data on the first side of the disk has been transferred to thememory has been reached. If the determined address has not been reached,the method continues reading the data from the first side of the disk instep 216. If the address of the determined point has been reached, thedata that was previously transferred to the memory in step 214 is readout to the system. While the data previously transferred to the memoryis read to the system in step 214, the reading of the disk is switchedbetween sides in step 222.

The switching between sides of the reading of the disk in step 222 willbe completed at approximately the same time as or before the data storedin the memory has finished being read in step 220, since the amount ofdata transferred to the memory will require at least the same amount oftime to be read out as it takes for the system to switch reading betweensides of the disk. This provides for access to the data stored thesecond side of the disk as soon as the data stored in the memory hasbeen read out to the system. When the data stored in the memory has beenread out to the system, the data from the second side of the disk isread in step 224.

Since data was read from the memory during the switching of the side ofthe disk being read, the data appears at a video screen which requiresthe output of the optical disk system to be continuous anduninterrupted. Thus, the method according to the present inventionprovides a seamless transition from a first side to a second side of anoptical disk without having a video picture stopped on a screen for theperiod of time it takes for the system to switch reading the databetween sides of the disk. Additionally, since only a small portion ofthe data stored on the first side of the disk is transferred to thememory, the size of the memory can be minimized to reduce the physicalsize and cost of the device.

It is important to note that while the embodiment as described abovedetermines the point at which the disk is to switch the reading of sidesand transfers a portion of the data at the end of the first side of thedisk before the data is read from the first side of the disk, theinvention is not to be so limited. The determination of the point atwhich the disk will be switched between sides in step 212 and thetransferring of the data to the memory in step 214 can occur at any timeafter the disk has been loaded into the optical reader, as long as it isperformed prior to the time the point determined in step 212 has beenreached in step 218.

FIG. 3 illustrates in block diagram form a processor system 300 in whichan optical disk device according to the present invention may beutilized. Such a system could include a computer system, stereo system,video game system, or a television system, all of which can utilize thepresent invention.

A processor system, such as a computer system for example, generallycomprises a central processing unit (CPU) 302 that communicates with aninput/output (I/O) device 304 over a bus 320. A second I/O device 306may also be provided. I/O devices 304, 306 may be, for example, a videodisplay or speaker. An optical disk device 308 for reading data storedon an optical disk 301 also communicates with the system over bus 320.Optical disk device 308 may also be combined with a processor, such as aCPU, digital signal processor or microprocessor, in a single integratedcircuit. The processor system 300 also includes a memory 310.

Processor system 300 is capable of providing continuous uninterruptedplayback of a dual sided optical disk utilizing the method of thepresent invention as described with respect to FIG. 2. CPU 302 willdetermine a point at which reading of dual sided optical disk 301 byoptical disk device 308 will be alternated between sides, and cause aportion of the data stored on the first side of the optical disk 301 tobe read and stored in memory 310. When the data from the optical disk301 is being read, the data stored in memory 310 will be read out to thesystem during the time the reading of optical disk 301 is switchedbetween sides, thus providing continuous uninterrupted playback ofoptical disk 301.

Reference has been made to preferred embodiments in describing theinvention. However, additions, deletions, substitutions, or othermodifications which would fall within the scope of the invention definedin the claims may be found by those skilled in the art and familiar withthe disclosure of the invention. Any modifications coming within thespirit and scope of the following claims are to be considered part ofthe present invention.

1-44. (canceled)
 45. A method comprising: storing a portion ofentertainment data read from a first non-volatile storage location,wherein the portion of entertainment data is stored in a memory; playingfirst entertainment data read from the first non-volatile storagelocation in substantially real-time; and playing second entertainmentdata read from a second non-volatile storage location in substantiallyreal-time, wherein the portion of entertainment data stored in thememory is played during a transition time between playing the first andsecond entertainment data read from the first and second non-volatilestorage locations.
 46. The method of claim 45 wherein the entertainmentdata stored in the first non-volatile storage location and theentertainment data stored in the second non-volatile storage locationcomprises a single set of data that is split between the first andsecond storage locations.
 47. The method of claim 45 wherein theentertainment data stored in the first non-volatile storage location andthe entertainment data stored in the second non-volatile storagelocation comprises two separate sets of data that are related, but notsplit, between the first and second storage locations.
 48. The method ofclaim 45 wherein the portion of entertainment data read from the firstnon-volatile storage location, the first entertainment data, and thesecond entertainment data comprise audio data.
 49. The method of claim45 wherein the portion of entertainment data read from the firstnon-volatile storage location, the first entertainment data, and thesecond entertainment data comprise visual data.
 50. The method of claim45 wherein the portion of entertainment data read from the firstnon-volatile storage location, the first entertainment data, and thesecond entertainment data comprise audiovisual data.
 51. The method ofclaim 45 wherein the first non-volatile storage location is at a firstside of a dual sided optical disk and the second non-volatile storagelocation is at a second side of the optical disk.
 52. The method ofclaim 51 wherein storing a portion of entertainment data in a memorycomprises storing a portion of entertainment data corresponding to datalocated at an end of the first side of the optical disk.
 53. The methodof claim 45 wherein playing the first entertainment data occurs beforethe transition time and before playing the second entertainment data.54. The method of claim 45 wherein playing the first entertainment data,playing the portion of the entertainment data stored in the memoryduring the transition time, and playing the second entertainment dataoccurs consecutively and without interruption.
 55. The method of claim45 wherein storing a portion of entertainment data in a memory comprisesstoring a portion of entertainment data having a size approximatelyequal to the transition time.
 56. A method of playing entertainment datain substantially real-time, the method comprising: storing a portion ofentertainment data in a memory, wherein the stored portion ofentertainment data is obtained from a first storage location; andplaying the stored portion of entertainment data during a transitiontime between playing the entertainment data from the first storagelocation and playing the entertainment data from a second storagelocation.
 57. The method of claim 56 wherein the first storage locationis on a first side of a dual sided optical disk and the second storagelocation in on a second side of the optical disk, and wherein: storing aportion of entertainment data in a memory comprises obtaining the storedportion of entertainment data from the first side of the optical disk;and playing the stored portion during a transition time comprisesplaying the stored portion during the period of time required for anoptical disk reader to switch from playing entertainment data from thefirst storage location on the first side of the optical disk to playingentertainment data from the second storage location on the second sideof the optical disk.
 58. The method of claim 56 wherein storing aportion of entertainment data in a memory comprises storing a portion ofentertainment data having a size corresponding to the amount of timerequired to access and begin playing the entertainment data form thesecond storage location after playing the entertainment data from thefirst storage location.
 59. A method of playing entertainment dataresiding in a first location and a second location in substantiallyreal-time, the method comprising: storing a portion of the entertainmentdata from the first location that is at least equal to the amount oftime required to transition from playing the entertainment data from thefirst location to playing the entertainment data from the secondlocation; playing the entertainment data from the first location exceptfor the stored portion of entertainment data; and playing the storedportion of entertainment data prior to playing the entertainment datafrom the second location.
 60. The method of claim 59 wherein the firstlocation comprises a first non-volatile storage location and the secondlocation comprises a second non-volatile storage location.
 61. Themethod of claim 60 wherein the first non-volatile storage locationcomprises a first side of an optical disk and the second non-volatilestorage location comprises a second side of the optical disk.
 62. Themethod of claim 59 wherein the entertainment data comprises audio data.63. The method of claim 59 wherein the entertainment data comprisesvisual data.
 64. The method of claim 59 wherein the entertainment datacomprises audio-visual data.
 65. The method of claim 59 wherein playingthe entertainment data from the first location, playing the storedportion of entertainment data, and playing second entertainment datafrom the second location occurs consecutively and without interruption.66. The method of claim 59 wherein storing a portion of theentertainment data from the first location comprises retrieving theentertainment data from a first side of an optical disk and storingentertainment data having a size approximately equal to a transitiontime between playing entertainment data from the first location andplaying entertainment data from the second location.